A genome-wide gene-environment interaction study of breast cancer risk for women of European ancestry

Leveraging GWAS: Path to Prevention?

Developing novel cancer prevention medication strategies is important for reducing mortality. Identification of common genetic variants associated with cancer risk suggests the potential to leverage these discoveries to define causal targets for cancer interception. Although each risk variant confers small increases in risk, researchers propose that blocking those that produce causal carcinogenic effects might have large impacts on cancer prevention. While a promising concept, we describe potential hurdles that may need to be scaled to reach this goal, including: (i) understanding the complexity of risk; (ii) achieving statistical power in studies with binary outcomes (cancer development: yes or no); (iii) characterization of cancer precursors; (iv) heterogeneity of cancer subtypes and the populations in which these diseases occur; (v) impact of static genetic markers across complex events of the life course; (vi) defining gene-gene and gene-environment interactions and (vii) demonstrating functional effects of markers in human populations. We assess short-term prospects for this research against the backdrop of these challenges and the potential to prevent cancer through other means. See related commentary by Peters and Tomlinson, p. 7.

Genes and environment: An old pair in a new era

What is the relationship between our genes and the environment we live in with regard to health? Like the debate about nature or nurture in the determination of our personality and behavior, the issue of genes and environment has been discussed intensely in the last two centuries. Is it Darwin or Lamarck who is right about the basic determinants of our health, especially as we age in a rapidly changing environment? Evolutionary biology as proposed by Darwin with natural selection at its core may not be able to explain almost instant adjustments of phenotypic traits to the pressures of the environment. Epigenesis, a concept that dates from Aristotle, provides a mechanism for the environment to affect variation in genetic traits that may become heritable. Indeed, Lamarck first described the inheritance of acquired characteristics. Thus, it appears that in contemporary genetics, both Darwin and Lamarck are right: environmental pressures may affect our genes through epigenetics, in ways that allow for inheritance of the changes, a Lamarckian concept; however, evolution through natural selection is the basis for incorporation (or rejection) of new traits and their sustained inheritance, a Darwinian concept. In this review, we present the synthesis of Darwin's and Lamarck's theories, the only way to understand how our health, and that of our progeny, responds to challenging and fast-changing environmental cues. In addition, we present other examples of environment-driven changes in disease frequency or expression.